Electric generator oil pump driven gear

ABSTRACT

A driven gear includes a radially outwardly extending flange. The radially outwardly extending flange extends along an axial distance defined along a center axis of the flange. The flange merges into a generally conical portion which, in turn, extends radially inwardly to a hub. The hub extends to a remote end. A first distance defined between the remote end of the hub and an end of the flange faces the remote end. A second distance is defined between ends of the flange, with gear teeth formed at an outer periphery. A ratio of the first distance to the second distance is between 2.54 and 2.82. An oil pump, a rotating portion for an electrical generator, and a generator are also disclosed.

BACKGROUND OF THE INVENTION

This application relates to details of a gear which is driven to, inturn, drive an oil pump for a generator.

Electrical generators are known and are often included in systems, suchas a gas turbine engine. The generator generates electricity for use onan associated system. As an example, the electrical generator maygenerate electricity to power the gas turbine engine and, further, foruses on an associated aircraft.

The generator includes a number of components which rotate at relativelyhigh speeds. Some generators may also be powered to begin rotation ofcomponents in the gas turbine engine for use as a starter.

Lubrication systems are known to provide lubricant to components withinthe electrical generator. In such systems, an oil pump is typicallydriven by a shaft from the electrical generator.

In one known type of electrical generator, a shaft which is driven aspart of the electrical generator carries a drive gear which engages adriven gear. The driven gear, in turn, rotates a pump rotor for an oilpump which delivers oil back to the generator.

In the prior art, there have been challenges with properly mounting thedrive and driven gears.

SUMMARY OF THE INVENTION

A driven gear drives a radially outwardly extending flange. The radiallyoutwardly extending flange extends along an axial distance defined alonga center axis of the flange. The flange merges into a generally conicalportion which, in turn, extends radially inwardly to a hub. The hubextends to a remote end. A first distance is defined between the remoteend of the hub and an end of the flange that faces the remote end. Asecond distance is defined between ends of the flange. Gear teeth areformed at an outer periphery of the flange. A ratio of the firstdistance to the second distance is between 2.54 and 2.824. An oil pump,a rotating portion for an electrical generator, and a generator are alsodisclosed.

These and other features may be best understood from the followingdrawings and specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a generator and a drive pump.

FIG. 2 shows a drive gear.

FIG. 3 is an end view of the FIG. 2 gear.

FIG. 4 shows a detail of a gear tooth.

FIG. 5 shows a driven gear.

FIG. 6 is an end view of the driven gear.

FIG. 7 shows a gear tooth for the driven gear.

DETAILED DESCRIPTION

FIG. 1 schematically shows a system 20 incorporating a gas turbineengine 22 which drives an electrical generator 24. The electricalgenerator 24 is driven by the gas turbine engine once the gas turbineengine is operating. In addition, as known, the generator 24 may also bedriven in an opposed direction to begin rotation of the gas turbineengine at start up.

A hub 26 rotates with a shaft of the electrical generator and the hub 26carries a drive gear 28. As shown, the drive gear 28 includes twodistinct internal bore surfaces 46 and 48 with distinct portions on thehub 26 to properly position the gear 28.

The gear 28 has gear teeth 32 which engage gear teeth 132 on a drivengear 30. Driven gear 30 is engaged to rotate a drive shaft 31 for an oilpump rotor 34. Oil pump rotor 34 is shown schematically delivering oilthrough line 36 back to components in the generator 24.

FIG. 1 further shows a rotor 302 which carries electrical components anda stator 300 which also carries electrical components. In one example,one of the components may be permanent magnets while the other iselectrical coils. These components operate, as known, to generateelectricity which is sent to a use 303, which may be to power the gasturbine engine 22 or may be for other uses on an aircraft.

FIG. 2 shows details of the drive gear 28. As shown, a hub extends fromend 38 to a remote end 42. The gear teeth 32 extend between the end 42and a ledge 40. A distance d₁ can be defined along an axis I between theends 40 and 42 and is also an axial extent of the teeth 32. The hubincludes a mount extending from the ledge 40 to end 38.

An axial distance between the end 42 and the end 38 is shown as d₂. Inone embodiment, d₁ was 0.220 inch (0.5588 centimeters) and d₂ was 0.423inch (1.074442 centimeters). In embodiments, a ratio of d₁ to d₂ isbetween 0.520 and 0.544. As further shown, cutouts 44 are formed in anend face at remote end 42. A ditch 50 is shown between the threadedradially inner bore portion 46 and the radially outer bore portion 48.

A diameter d₃ to an outer diameter of the gear teeth 32 was 1.60 inches(4.06 centimeters). A ratio of d₃ to d₁ was between 6.93 and 7.28.

FIG. 3 shows an end of the drive gear 28 and shows there are four equalspaced cutouts 44, which are all cylindrical.

FIG. 4 shows a detail of a gear tooth 32. As shown, there are curvedsides 200 and a relatively flat end 202. The curved sides 200 includefour roll angles. A roll angle from a base of the side 200 to the pointA was 7.66°. In embodiments, this roll angle is between 6.66 and 8.66. Aroll angle X to the point B from the base of the side was 12.10° in oneembodiment. In embodiments, the roll angle X was between 11.1° and13.1°. A roll angle Y to the point C was 25.4° in one embodiment. Inembodiments, the roll angle Y was between 24.4° and 25.4°. Finally, theroll angle Z to the point D at the outer end of the side 200 was 29.9°.In embodiments, the angle Z was between 28.9° and 30.9°. Points A-Drepresent locations along the tooth where roll angles are inspected withA at tooth base, and D at tooth tip.

FIG. 5 shows details of the driven gear 30. The gear teeth 132 are at anouter periphery and extend between an end 60 to an end 70 of a radiallyoutwardly extending flange 60. Holes 62 extend through the flange 60.

A generally conical portion 64 merges the flange 60 into a base or hub66. The hub 66 defines a remote end 68. A distance d₁ is defined along acentral axis J between ends 68 and 70. A second diameter d₂ is definedalong the axis J between ends 70 and 72. In one embodiment, d₁ was 0.348inch (0.88392 centimeters) and d₂ was 0.130 inch (0.3302 centimeters).In embodiments, a ratio of d₁ to d₂ was between 2.541 and 2.824.

FIG. 6 shows an end view of the gear 30. As shown, there are eight holes62 each equally spaced about the axis J. The central hole 67 has opposedcylindrical portions 70 and intermediate flat portions 69. A distance tod₃ is defined through the axis J and between the flat portions 69. Inone embodiment, d₃ is 0.378 inch (0.96 centimeters). In embodiments, aratio of d₃ to d₁ was between 1.06 and 1.10 inches (2.69 and 2.79centimeters).

As shown in FIG. 7, the gear tooth 132 has angles L, M, N and O. In oneembodiment, the angle L to the point A along the side 202 was 14.42°. Inembodiments, the angle L was between 13.42° and 15.42°. In oneembodiment, a roll angle M to the point B was 16.7°. In embodiments, theroll angle M is between 15.7° and 17.7°. In an embodiment, the rollangle N to the point C was 23.54°. In embodiments, the roll angle N isbetween 22.54° and 24.54°. In an embodiment, the roll angle O to thepoint D was 25.82°. In embodiments, the roll angle O is between 24.82°and 26.82°.

With the disclosed sizing and location of the various components, thelocation of the gears 30 and 28 on the respective shafts is proper. Inaddition, the roll angles result in the gears transmitting rotation moreeffectively.

Although an embodiment of this invention has been disclosed, a worker ofordinary skill in this art would recognize that certain modificationswould come within the scope of this invention. For that reason, thefollowing claims should be studied to determine the true scope andcontent of this invention.

1. A driven gear to drive an oil pump for a generator comprising: adriven gear including a radially outwardly extending flange, saidradially outwardly extending flange extending along an axial distancedefined along a center axis of said flange, said flange merging into agenerally conical portion which, in turn, extends radially inwardly to ahub, said hub extending to a remote end, and a first distance definedbetween said remote end of said hub and an end of said flange facingsaid remote end, and a second distance defined between ends of saidflange, with gear teeth formed at an outer periphery of said flange; anda ratio of said first distance to said second distance being between2.54 and 2.82.
 2. The driven gear as set forth in claim 1, wherein saidgear teeth have a flat outer end and curved sides, with there being fourroll angles on each of said sides, with a first roll angle extending for13.4° to 15.4°, a second roll angle extending for 15.7° to 17.7°, athird roll angle extending for 22.5° to 24.5°, and a fourth roll angleextending for 24.8° to 26.8°.
 3. The driven gear as set forth in claim2, wherein there are holes extending through said flange.
 4. The drivengear as set forth in claim 3, wherein there eight of said holes allbeing cylindrical and equally spaced about the central axis.
 5. Thedriven gear as set forth in claim 4, wherein a central bore in said hubincludes a pair of generally cylindrical portions extending about aportion of said axis, and opposed flat portions between said generallycylindrical portions.
 6. The driven gear as set forth in claim 5,wherein said flat portions are spaced by a distance between 0.375 and0.378 inches (0.95 and 0.96 centimeters).
 7. An oil pump for use in agenerator comprising: a drive gear to be driven by a generator shaft andsaid drive gear engaging a driven gear, said driven gear driving a pumprotor; and said driven gear including a radially outwardly extendingflange, said radially outwardly extending flange extending along anaxial distance defined along a center axis of said flange, said flangemerging into a generally conical portion which, in turn, extendsradially inwardly to a hub, said hub extending to a remote end, and afirst distance defined between said remote end of said hub and an end ofsaid flange facing said remote end, and a second distance definedbetween ends of said flange, with gear teeth formed at an outerperiphery of said flange, and a ratio of said first distance to saidsecond distance being between 2.54 and 2.82.
 8. The oil pump as setforth in claim 7, wherein said gear teeth have a flat outer end andcurved sides, with there being four roll angles on each of said sides,with a first roll angle extending for 13.4° to 15.4°, a second rollangle extending for 15.7° to 17.7°, a third roll angle extending for22.5° to 24.5°, and a fourth roll angle extending for 24.8° to 26.8°. 9.The oil pump as set forth in claim 8, wherein there are holes extendingthrough said flange.
 10. The oil pump as set forth in claim 9, whereinthere eight of said holes all being cylindrical and equally spaced aboutthe central axis.
 11. The oil pump as set forth in claim 10, wherein acentral bore in said hub includes a pair of generally cylindricalportions extending about a portion of said axis, and opposed flatportions between said generally cylindrical portions.
 12. The oil pumpas set forth in claim 11, wherein said flat portions are spaced by adistance between 0.375 and 0.378 inches (0.95 and 0.96 centimeters). 13.A rotating portion for an electrical generator comprising: a rotor hubcarrying a drive gear to engage a driven gear; and said driven geardriving an oil pump rotor, said driven gear including a radiallyoutwardly extending flange, said radially outwardly extending flangeextending along an axial distance defined along a center axis of saidflange, said flange merging into a generally conical portion which, inturn, extends radially inwardly to a hub, said hub extending to a remoteend, and a first distance defined between said remote end of said huband an end of said flange facing said remote end, and a second distancedefined between ends of said flange, with gear teeth formed at an outerperiphery of said flange, and a ratio of said first distance to saidsecond distance being between 2.5 and 2.8.
 14. The rotating portion foran electrical generator as set forth in claim 13, wherein said gearteeth have a flat outer end and curved sides, with there being four rollangles on each of said sides, with a first roll angle extending for13.4° to 15.4°, a second roll angle extending for 15.7° to 17.7°, athird roll angle extending for 22.5° to 24.5°, and a fourth roll angleextending for 24.8° to 26.8°.
 15. The rotating portion for an electricalgenerator as set forth in claim 14, wherein there are holes extendingthrough said flange.
 16. The rotating portion for an electricalgenerator as set forth in claim 15, wherein there eight of said holesall being cylindrical and equally spaced about the central axis.
 17. Agenerator comprising: a stator, and a rotor, electrical components onsaid stator and said rotor interacting to generate electricity when saidrotor is rotated, said rotor having a rotor hub, said rotor hub carryinga drive gear, the drive gear engaging a driven gear which drives an oilpump; said driven gear to drive an oil pump for a generator, said drivengear including a radially outwardly extending flange, said radiallyoutwardly extending flange extending along an axial distance definedalong a center axis of said flange, said flange merging into a generallyconical portion which, in turn, extends radially inwardly to a hub, saidhub extending to a remote end, and a first distance defined between saidremote end of said hub and an end of said flange facing said remote end,and a second distance defined between ends of said flange, with gearteeth formed at an outer periphery of said flange; and a ratio of saidfirst distance to said second distance being between 2.54 and 2.82. 18.The generator as set forth in claim 17, wherein said gear teeth have aflat outer end and curved sides, with there being four roll angles oneach of said sides, with a first roll angle extending for 13.4° to15.4°, a second roll angle extending for 15.7° to 17.7°, a third rollangle extending for 22.5° to 24.5°, and a fourth roll angle extendingfor 14.8° to 26.8°.
 19. The generator as set forth in claim 18, whereinthere are holes extending through said flange.
 20. The generator as setforth in claim 19, wherein there eight of said holes all beingcylindrical and equally spaced about the central axis.